This invention relates to alumina ceramic articles containing dispersed metal for use as cutting tools, wear parts, and the like. In particular the invention relates to such articles containing a metal including both nickel and aluminum.
Ceramic-metal (cermet) tools for steel machining have greatly improved the productivity and efficiency of the metal removal process. The performance of a number of cermet materials, which principally are based on refractory metal carbides or nitrides bonded with cobalt, nickel, molybdenum, or alloy binders, inherently is limited by the chemical interaction between the hard phase and steel workpiece materials. This becomes particularly evident as increased cutting speeds generate more heat, increasing the chemical reactivity of both the tool material and the workpiece. Such chemical reactions between the cutting tool and steel workpiece accelerate wear and reduce crater resistance of the tool.
Attempts have been made to utilize alumina ceramics and alumina-based composites such as alumina-titanium carbide composites for use as cutting tools for steel machining. The broader use of this class of materials, however, has been restricted by their inherently low fracture toughness.
Accordingly, it would be of great value to find a cermet material suitable for cutting tool use which exhibits improved fracture toughness compared to known alumina-titanium carbide composites as well as improved chemical wear resistance and performance compared to conventional cermet cutting tool materials. Such a new and improved cermet material is described herein.